1. Field of the Invention
The present invention relates to systems for utilizing the energy in ocean waves and the like, and in particular to apparatus for converting such wave energy into electrical energy.
2. Description of the Prior Art
Several schemes have been devised in the prior art for converting the wave motion energy of a body of water into electrical energy. One scheme uses wave motion energy of tidal differences to raise water in a reservoir; the water in the reservoir is then used to drive a turbine. See, for example, U.S. Pat. Nos. 2,668,918; 2,820,148; 2,871,790; and 3,487,228. A second scheme utilizes wave motion energy to pump or compress air or water which, in turn, drives a turbine. See, for example, U.S. Pat. Nos. 427,398; 901,117; 3,569,725; 3,064,137; and 3,200, 255. A third scheme utilizes the periodic motion of the waves to rotate various gears which in turn drive an electrical generator. See, for example, U.S. Pat. Nos. 3,204,110 and 3,231,749. The fourth scheme employs the horizontal vector element of wave motion energy to turn a shaft which then drives a turbine. See, for example, U.S. Pat. Nos. 833,361; 988,508; and 1,289,533. The fifth arrangement utilizes the energy in the differential height of the tide to drive a gear arrangement, or to provide the differential motion between magnets and fields coils. See, for example U.S. Pat. Nos. 3,011,062 and 3,567,953.
A further technique employs two concentric buoys; a first buoy is anchored and maintains a fixed position, while the second buoy is buoyantly supported by, and moves with, the wave motion on the surface of the body of water. A magnet is mounted in one buoy and a field coil is mounted in the other, so that the relative motion between the buoys generates an electromotive force. This technique is disclosed by Rich in U.S. Pat. No. 3,546,473.
An early U.S. Pat. No. 628,457 to Gehre discloses a rudimentary wave generator, which uses single induction coils on a small, floating system. The floating system has the obvious disadvantage of depending on the inertia of the platform and is thus relatively inefficient, since it is sensitive to horizontal motion of the water surface.
In a related apparatus, developed by the present inventor and described in U.S. Pat. No. 3,783,302, an expandable and flexible coil is supported on one end by a platform which reciprocates in response to the wave motion across the surface of a body of water. A magnetic field is provided through the coil so that an electromotive force is generated therein due to the relative motion between the coil and the magnetic field.